Insect muscles and how they can change sci-fi/fantasy

I’m all for sci-fi/fantasy creatures inspired by real Earth animals. Just look at my own korvi folk, the bird-like dragons based on Earth’s own archosaurs. And look at the strangeness of sea creatures such as the nudibranchs. But we don’t need to look hard for inspiration in the deepest oceans and the distant past. Even a simple grasshopper can challenge what we know to be true about animal life.

In a study published today in the journal Current Biology, the researchers show that the structure of some insect leg joints causes the legs to move even in the absence of muscles. So-called ‘passive joint forces’ serve to return the limb back towards a preferred resting position. The passive movements differ in limbs that have different behavioural roles and different musculature, suggesting that the joint structures are specifically adapted to complement muscle forces.

Basically, some sections of insect legs are just hard structures that flex under pressure and spring back into place — like a wooden ruler bent and released. This is more effective than muscle contraction alone when a sharp, powerful motion is needed.

But it certainly challenges our idea that muscles are responsible for movement. Mammals use structures like elastic tendons to store energy for quick movements, but there are further possibilities when an exoskeleton is involved. (And when the creature is as small and light as an Earth insect. As the ant demonstrates when it lifts many times its body weight, physics are less constraining the smaller you are.)

I think ideas like this have enormous potential in SFF writing. Sci-fi obviously delves into real science, hence the genre’s name. But fantasy can use it, too. How better to explain a being’s strange, amazing abilities than to make its body different from a human’s? What could people find if they cut a monster up and examine its parts? Or tend to another race’s wounds?

This is part of why I’m still sketchy on the exact details of my aemet race’s anatomy. I’ve been fascinated by dinosaurs and birds long enough to have a pretty good grasp on how korvi work. And ferrin are ordinary by mammal standards. Aemets, though … I always feel like the Aligare world’s insect/mammal fusions — the betweenkind creatures — should have structures that a human finds alien. Probably some biological tricks I’m not aware of. This idea of leg strength not always coming from muscles? That could very well be one of aemetkind’s secrets. My pacifistic folk could have leg joints more similar to a grasshopper’s than a human’s — the better for them to bolt away from danger.

Ideas like this make me hopeful that speculative fiction will never run out of ways to innovate. When a simple action like jumping can hold mechanical surprises, I don’t think we have any excuse to settle for the same old stuff we’ve been assuming forever.